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Food safety remains one of the most important issues in most countries and the detection of food hazards plays a key role in the systematic approach to ensuring food safety. Rapid, easy-to-use and low-cost analytical tools are required to detect chemical hazards in foods. As a promising candidate, microfluidic paper-based analytical devices (μPADs) have been rarely applied to real food samples for testing chemical hazards, although numerous papers have been published in this field in the last decade. This review discusses the current status and concerns of the μPAD applications in the detection of chemical hazards in foods from the perspective of food scientists, mainly for an audience with a background in mechanical and chemical engineering who may have interests in exploring the potential of μPAD to address real-world food safety issues.

Methicillin-resistant Staphylococcus aureus (MRSA) is considered as one of the leading causes of food poisonings worldwide. Due to the high prevalence and extensive challenges in clinical treatment, a rapid and accurate detection method is required to differentiate MRSA from other S. aureus isolated from foods. Since the methicillin resistance of S. aureus is due to the acquisition of the mecA gene from staphylococcal chromosome cassette, the presence of the mecA gene is interpreted as a marker for the identification of MRSA. In this study, a low-cost lateral flow immunoassay (LFI) strip was used to detect the mecA amplicons subsequent to polymerase chain reaction (PCR). The specificity of this PCR-LFI assay was tested between MRSA and methicillin-susceptive S. aureus. Both the test line and control line were shown up on the LFI strip for MRSA, whereas only the control line developed for methicillin-susceptive S. aureus. The detection limit of PCR-LFI assay was 20fg for genomic DNA (100 times more sensitive than gel electrophoresis) and 2×10CFU per 100g of pork products after enrichment at 37°C for 48h. The total detection time of using LFI was 3min, which was faster than the conventional electrophoresis (~45min). With the performance of PCR-LFI, 7 out of 42 S. aureus isolates were identified to be MRSA from imported pork products, which was consistent to the standardized minimum inhibitory concentration assay. This mecA-based PCR-LFI strip can be used for rapid and accurate detection of MRSA isolated from commercial pork products.

The developed species-specific polymerase chain reaction-lateral flow immunoassay (PCR-LFI) method allows the rapid, low-cost, highly sensitive and specific detection of donkey DNA for meat authentication, adopted by government laboratories.